In past studies of international relations of the pre-Pacific War, stress was laid on Japan's advance into southern French Indo-China and the decision taken to impose an oil embargo against Japan, which was a countermeasure against it, as decisive incidents in the Japan-United States confrontation. But, as is made clear by the above, the Japan-United States confrontation must be studied from the overall viewpoint of the history of twentieth-century international relations, with United States-Soviet relations as a basic factor.
In that sense, July 10, when President F.D. Roosevelt conferred with So- viet Ambassador in Washington C. Oumansky, was a noteworthy day from the standpoint of the history of United States-Soviet relations. For, on that day, an important conference signifying the first step toward the formation of a United States-Britain-Soviet union in World War II was held.
When viewed in this way, it can be concluded that on July 9 or 10 after a period of indecision immediately after the outbreak of the German-Soviet War, the President decided on rapprochement with Soviet Russia, judging that the latter's resistance to Germany would tally with America's national interests, that, as a United States-Britain-Soviet union could be thus formed, appeasement of Japan would become unnecessary, that a foundation enabling her to employ a firm policy toward Japan was therefore established, and that these circumstances were reflected in America's attitude toward the later Japan-United States nego- tiations.
Of course, the President could not ignore the influence of isolationists. So it seems he shied away from making a definite promise of armed aid to British Prime Minster Winston S. Churchill in the Atlantic conference held later. 18
But, it can be concluded that the President secretly decided to assume a firmer policy toward Japan before or after July 9 or 10 when he determined to give aid to Russia. This view is taken by a French historian, Pierre Renouvin, too. He states as follows:
"The stiffening of American policy, as witnessed by the economic and fi- nancial sanctions imposed at the end of July, was evidently determined by the new turn of events in the European war - namely, the break in relations between the U.S.S.R. and Germany. " 19
P. Renouvin does not clearly show his grounds for this assertion, but that judgement is convincing through the above examination.
In short, it must not be forgotten that in America's foreign policy, stress was laid on the European problem aiming at the overthrow of Hitler, and that the weight of her policy toward Japan was secondary compared with her policy to- ward Europe. From this point of view, after all, it can be said that it was no more